3-D printing, which works by building parts in layers, is a process used for the building up of 3-D models. 3-D printing is relatively speedy and flexible allowing for the production of prototype parts and tooling directly from a CAD model, for example.
Using 3-D printing enables the manufacturer to obtain a full 3-D model of any proposed product before tooling thereby possibly substantially reducing the cost of tooling and leading to a better synchronization between design and manufacturing. A lower product cost and improved product quality can also be obtained.
Various systems have been developed for computerized 3-D printing. Known systems include a system developed by 3-D Systems Inc. of California, USA. which operates on the basis of stereo-lithography wherein a focused ultra-violet laser is scanned over the top of a bath of photopolymerizable liquid polymer plastic material. The surface of the bath is polymerized on contact with the UV laser creating a solid plastic layer at or just below the surface
U.S. Pat. No. 5,387,380 to Cima et al. describes a technique for providing layered parts by depositing a layer of powder material and then depositing a binder material in selected regions to produce a layer of bonded powder material at the selected regions. These steps are repeated for successive layers to form a desired component. Following heat treatment, unbound powder is removed, leaving the fabricated part.
U.S. Pat. No. 5,287,435 to Cohen et al describes apparatus for producing 3-D models which includes apparatus for depositing layer-by-layer, a photopolymer material in a selectable configuration and apparatus for curing each layer prior to deposition of the succeeding layer.
A disadvantage of this system is that it is difficult to achieve a flat uniform surface for each layer. U.S. Pat. No. 5,287,435 utilizes a machining unit for trimming the surface of each layer to remove excessive thickness.
In standard two-dimensional printing, the ink jet printer prints parallel ink. dot lines on a substrate by displacing its print head relative to a substrate in one direction during the actuation of its ink jet heads.
In U.S. patent application Ser. No. 09/259,323 to the Assignees of the present application, and incorporated herein by reference, there is described an apparatus and a method for 3-D model printing. U.S. patent application Ser. No. 09/259,323, now issued as U.S. Pat. No. 6,259,962, describes apparatus including a printing head having a plurality of nozzles, a dispenser connected to the printing head for selectively dispensing interface material in layers and curing apparatus for optionally curing each of the layers deposited. The depth of each deposited layer is controllable by selectively adjusting the output from each of the plurality of nozzles.
In U.S. patent application Ser. No. 09/412,618 to the Assignees of the present application, and incorporated herein by reference, there is described an apparatus and a method for 3-D model printing. U.S. patent application Ser. No. 09/412,618 describes a system and a method for printing complex 3-D models by using interface material having different hardness or elasticity and mixing the interface material from each of the printing heads to control the hardness of the material forming the 3-D model.